(Invited) Thermal Actuation in Battery Energy Storage

Thermal actuation in electrochemical batteries is a new method to modulate internal states and interfaces on demand for game-changing energy efficiency, power, lifetime, and safety of next-generation energy storage systems. In this talk we shall explore fundamentals and applications of thermal actuation. The scientific principle of thermal actuation in advanced batteries is rooted in the battery materials’ heat capacity, averaged at ~900 J/kg*K or equivalently 0.25 Wh/kgK. This means that for every o C temperature rise, there is only 0.1% SOC energy consumption for 250 Wh/kg current batteries or 0.05% SOC for 500 Wh/kg next-gen cells. Thus, on average the energy cost to raise 10 o C battery temperature is only 0.75% SOC consumption! Moreover, to discharge 0.75% SOC takes 27, 9 and 4.5 seconds at 1C, 3C and 6C, respectively, thereby yielding heating rates of 22, 66 and 133 o C/min. These heating rates of intracell thermal actuation are amazingly 20-130 times of ~1 o C/min external heating. Benefits of 10 o C temperature rise in batteries are tremendous, including doubling power or halving internal resistance. Thus, the power-energy ratio of thermal actuation is on the order of 100! Furthermore, it takes only 5-30 seconds to obtain doubling power via thermal actuation. Such a new way to deliver high power on demand promises for numerous applications in decarbonizing transportation and the electrical grid. We shall discuss some initial examples such as: (1) all-climate batteries (ACB) to deliver room-temperature power even at as low temperatures as -40 o C; (2) 6C fast charging batteries (FCB) regardless of ambient temperatures (between -50 and 60 o C) and energy density; (3) heat-tolerant batteries (HTB) that survive hot summers while eliminating refrigerant or liquid cooling. More broadly, we will present a materials and control co-design (MC2D) framework for battery energy storage to capture unprecedented innovations.